This is a fact. Have you ever looked at an older circuit board? The flow of electricity changes the board. I have installed many cameras that had perfect focus and have returned two weeks later to find them out of focus. Gremlins perhaps! The question is: How much does the sound actually change? Does the tone change from harsh to smooth? Does the bass change from thin to deep? Does the soundstage come into focus? If I had to guess, from my own experience, it is 5 to 10 percent at the most.
Tim
Tim